In order to measure a position, a distance, and the like regarding a moving object such as a vehicle, a robot, or an animal, there are various technologies, one of which uses a plurality of image capturing apparatuses to capture images of the object from different angles with synchronized timing. The above technology can measure, for example, a distance from the object to each image capturing apparatus by triangulation using a focal length of each imaging apparatus lens and a parameter such as a distance between the image capturing apparatuses. The above-mentioned “to capture with synchronized timing” means that a picture obtained by a first image capturing apparatus and another picture obtained by a second image capturing apparatus are captured (sampled) with exact coincidence in time.
One such technology for the synchronized capturing by a plurality of image capturing apparatuses is disclosed in Japanese Patent Laid-Open No. 2000-341719 publication to provide a stereo camera.
FIG. 1 is a diagram showing a structure of the conventional stereo cameras.
Referring to FIG. 1, lenses 701-1 and 701-2 focus respective collected light. Imaging devices 702-1 and 702-2 convert the light focused by the lenses 701-1 and 701-2 into respective electrical signals. Signal processing units 703-1 and 703-2 convert, into respective image signals, the electrical signals which are outputted from the imaging devices 702-1 and 702-2. A drive signal generation unit 704 generates a drive signal for driving both of the imaging devices 702-1 and 702-2, and both of the signal processing units 703-1 and 703-2. An imaging apparatus 705-1 includes the lens 701-1, the imaging device 702-1, the signal processing unit 703-1, and the drive signal generation unit 704. An imaging apparatus 705-2 includes the lens 701-2, the imaging device 702-2, and the signal processing unit 703-2. An image processing unit 706 processes images from both of the image signals which are outputted from the imaging apparatuses 705-1 and 705-2.
Here, in the imaging apparatuses 705-1 and 705-2, the light focused by the lenses 701-1 and 701-2 are converted into electrical signals by the imaging devices 702-1 and 702-2 which are driven by the drive signal generated by the drive signal generation unit 704. The electrical signals converted by the imaging devices 702-1 and 702-2 are converted into the image signals by the signal processing units 703-1 and 703-2 which are driven by the drive signal generated by the drive signal generation unit 704. The image signals converted by the signal processing units 703-1 and 703-2 are inputted into the image processing unit 706 which processes images from both of the image signals.
According to the conventional technology, in the imaging apparatuses 705-1 and 705-2, the drive signal which is generated by the same drive signal generation unit 704 is used to drive both of the imaging devices 702-1 and 702-2 and both of the signal processing units 703-1 and 703-2, so that the imaging apparatuses 705-1 and 705-2 can capture images of the same object with synchronized timing.
However, in such a conventional technology, it is necessary to establish signal lines for supplying the drive signal generated by the drive signal generation unit to the respective imaging apparatuses, for example, if there are Q imaging apparatuses (Q is a whole number), it is necessary to establish Q signal lines for supplying the synchronizing signal and the drive signal to these imaging apparatuses, so that the greater a distance between the imaging apparatuses is, the longer the signal line is required to be, which results in problems of increased cost and installation load. Especially in a case that a plurality of imaging apparatuses are installed in a large space, for example, in order to capture images of a football player in a football stadium, it is necessary to connect the respective imaging apparatuses to be supplied with the synchronizing signal and the drive signal, which causes a significant cost and extra cable installation work.